From BBC News Online, Ansett has grounded all their 767s for "unspecified saftey checks". Hmmm.

Here's an extract

"Air travel in Australia is being disrupted for a second consecutive day at one of the busiest times of the year - this time by the grounding of six aircraft by one of the country's main airlines.
The Boeing 767s were taken out of service for unspecified safety checks.

The airline, Ansett Australia, gave no reason for the mechanical checks, which are disrupting the Christmas travel plans of thousands of passengers. "